1. Field of the Invention
The present invention relates to a liquid crystal display device, or more particularly, to a technology for reducing the external dimensions of a compact display device set for portable cellular phones or the like.
2. Description of the Related Art
As for liquid crystal display devices, there is an intense demand for reduction in the external dimensions of a display device set with a certain size of a screen kept intact. A liquid crystal display device for portable cellular phones or any other display device whose set should have the external size thereof made small is especially intensely demanded to have small external dimensions.
FIG. 24 is a plan view of a module of a conventional compact liquid crystal display device to be used for portable cellular phones. In FIG. 24, a liquid crystal display panel includes a TFT substrate 1 in which pixel electrodes, thin-film transistors (TFTs), data signal lines, and scan lines are formed, a color filter substrate 2 in which color filters or the like are formed, an upper sheet polarizer 7 bonded to the color filter substrate 2, and a lower sheet polarizer 8 that is not shown and is bonded to the bottom of the TFT substrate 1. The portions of the substrates to which the sheet polarizers are bonded may be considered as an effective field in which an image is formed. The TFT substrate 1 is made larger than the color filter substrate 2 in order to attach an IC driver 4 which drives the liquid crystal display panel, and a flexible wiring substrate, which is used to feed power or signals to the liquid crystal display panel, to the TFT substrate 1.
A backlight that irradiates light to the liquid crystal display panel from behind is disposed under the lower sheet polarizer 8. The liquid crystal display panel and backlight are stored in a resin mold 5. The flexible wiring substrate 3 attached to the TFT substrate 1 is folded up to the back of the resin mold 5 while covering the short-side part of the resin mold 5. In FIG. 21, the edge of the folded flexible wiring substrate 3 is seen.
The resin mold 5 in which the liquid crystal display panel and backlight are stored, and the flexible wiring substrate are stored in a frame usually made of a metal.
As a literature in which the foregoing structure is described, Japanese Patent Application Laid-Open Publication No. 2005-338497 is taken for instance.
The demand that the exterior of a display device should be made smaller with a certain size of a screen kept intact is getting more and more intense. In FIG. 24, as a means for further reducing the exterior, it is conceivable to, for example, decrease the thickness of the flank of the resin mold 5. The resin mold 5 is manufactured by performing injection molding. A lower limit of thicknesses to be attained through fabrication based on the injection molding is 0.45 mm. For a thickness equal to or smaller than 0.45 mm, the injection molding cannot be employed. Consequently, there are limitations in reducing the exterior of the conventional structure shown in FIG. 24.
If the resin mold 5 interposed between the liquid crystal display panel and the frame 6 is excluded, the exterior of the frame 6 can be reduced by a magnitude equivalent to the thickness of the resin mold 5. However, in this case, the color filter substrate 2 or TFT substrate 1 that is made of a glass and the frame 6 that is made of a metal would come into direct contact with each other. When a metal and a glass come into contact with each other, there is a risk that the glass may be cracked. In particular, if minute cracks were formed on an edge of a glass substrate, it would be quite hazardous.
Consequently, as long as the foregoing conventional structure is adopted, an attempt of reducing an exterior confronts limitations. If the exterior were reduced, it would bring about the risk that the glass substrate of the liquid crystal display panel may be cracked.